Skew quadrupole effects in the IBM compact synchrotron

The normal operating condition for the IBM X-ray source is to have a skew quadrupole magnet energized to a focal length of 20 m. This paper details the effects seen by synchrotron light monitors as a consequence of varying the strength of this magnet. In particular, the cross section of the electron beam appears vertically expanded and tilted. Furthermore, these effects are slightly different in the two dipole magnets. These effects can be understood by deriving the normal modes for the linearly coupled betatron motions for the case of operation far from a coupling resonance line.< >